Crystal Engineering: Synthesis and Structural Analysis of Coordination Polymers with Wavelike Properties

Polymers

Omar W. Steward¹  Miles V. Kaltenbach²  Ashley B. Biernesser²  Matthew J. Taylor²  Katie J. Hovan²  Jordan J. S. VerPlank²  Ameera Haamid²  Irina Karpov² 

[1] Department of Chemistry and Biochemistry, Bayer School of Natural and Environmental Sciences, 600 Forbes Avenue, Duquesne University, Pittsburgh, PA 15282, USA;

关键词: crystal engineering;    wavelike polymers;    sine function;    wavelength;    amplitude;    coordination polymers;   

DOI  :  10.3390/polym3041662

来源: mdpi

【 摘 要 】

Supramolecular coordination polymers with wavelike structures have been synthesized by self-assembly and their structures analyzed using the sine trigonometric function. Slow evaporation of a methylene chloride-methanol solution of a 1:1 molar mixture of [M(tmhd)₂], where M = Co or Ni, and quinoxaline; a 1:2:1 molar mixture of [M(acac)₂], where M = Co or Ni, 2,2,6,6-tetramethyl-3,5-heptadione and quinoxaline; or a 1:2:1 molar mixture of [Co(acac)₂], dibenzoylmethane, and quinoxaline, yielded the crystalline coordination polymers. In the presence of the nitrogenous base, ligand scrambling occurs yielding the most insoluble product. The synthesis and structures of the following wavelike polymers are reported: trans-[Co(DBM)₂(qox)]_n·nH₂O (2), trans-[Co(tmhd)₂(qox)]_n (3), trans-[Ni(tmhd)₂(qox)]_n (4), where DBM^-= dibenzoylmethanate, tmhd^- = 2,2,6,6-tetramethyl-3,5-heptadionate, and qox = quinoxaline. The wavelike structures are generated by intramolecular steric interactions and crystal packing forces between the chains. Some of the tert-butyl groups show a two-fold disorder. The sine function, φ = A sin 2πx/λ, where φ = distance (Ǻ) along the polymer backbone, λ = wavelength (Ǻ), A = amplitude (Ǻ), x = distance (Ǻ) along the polymer axis, provides a method to approximate and visualize the polymer structures.

【 授权许可】

CC BY   
© 2011 by the authors; licensee MDPI, Basel, Switzerland.